Sheet-shaped documents of value can be for example bank notes, checks, share certificates, tickets, coupons, deeds, vouchers, high-quality admission tickets, but also other papers at risk of forgery, such as passports or other identification documents, or also security papers not yet or not yet completely printed or otherwise processed which are used for producing e.g. bank notes. Although not restricted to it, in the following by way of example bank notes are described as such documents of value.
Within the terms of the present invention, a luminescent feature substance is a substance consisting of one single component or of a mixture of a plurality of components which show a luminescence behavior.
Such luminescent feature substances usually are incorporated directly into the paper or the printing ink for printing the bank notes.
For criminal purposes it is helpful, when for the protection of bank notes feature substances are used which are detectable even after the combustion of the document, in order to being able to ensure that an unrecognizable residue of combustion really originates from authentic documents. On the other hand it must be prevented, that the feature substances contained in the ashes of the burnt documents of value are regained and used for the preparation of forgeries.
For solving this problem according to the WO 00/39397 A1 of the applicant it is proposed to provide a document of value with a first machine checkable physical or chemical property and with a second machine checkable physical or chemical property, the first and second checkable property being machine checkable separately from each other, the document of value losing the first checkable property at a first temperature, and the document of value losing the second checkable property at a second temperature which is different from the first temperature.
For this purpose, however, there are relatively few suitable feature substances. Therefore, there is a demand for alternatives hereto, so that a larger group of feature substances can be used for protecting the authenticity of documents of value.
Therefore, it is a problem of the present invention to provide an alternative sheet-shaped document of value having luminescent feature substance, which after ashing cannot be used for the production of forgeries without an unreasonably high effort. In addition, the manufacturing and checking of such a document of value is stated.